Foldable Bikes Party: Five soft-riding road seatposts tested in the lab and on the road

Wednesday, 17 February 2016

Five soft-riding road seatposts tested in the lab and on the road

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There are lots of seatpost options these days that promise a more comfortable ride without the complication (and weight) of mechanical pivots or sliding bits. But which ones actually work, and which are just hype? We enlisted the help of Microbac Laboratories in Boulder, Colorado to find out which of the new crop of soft-riding rigid seatposts does the best job of saving your butt.

For all the work that road bike designers put into making their frames more comfortable, the simple fact remains that their triangulated tube layouts make them inherently resistant to movement under vertical loads. Seatposts, on the other hand, are simple cantilevered tubes with no additional bracing, meaning they’re free to flap about in the breeze and far more apt to move when you hit something.

A bicycle frame's triangulated arrangement of tubes doesn't allow for much flex. A seatpost, however, is much more free to move under load

Of course, all seatposts are not created equal – even when they share critical dimensions such as diameter and length – and component engineers have recently started to capitalise more thoroughly on the design possibilities of carbon fibre composites. Fibre lay-ups and even the fibre types themselves can be tuned to allow more flex in one plane than another, for example, while more elaborate designs cleverly incorporate mechanisms to promote movement without the complexity (and weight) of physical pivots, springs, and dampers.

Road bikes don’t generally have to deal with much in terms of bump amplitude, though, so while some companies have focused on taking the edge off of bigger hits, others have decided to concentrate on canceling out annoying vibrations that come with coarsely paved asphalt – that incessant buzzing that might not have much effect at first but can really become irritating after a couple of hours.

The contenders

Canyon VCLS: Canyon’s entry has actually been around for several years now – so long, in fact, that the company no longer offers it as an aftermarket product but still includes it on many of its complete bikes. Instead of only using carbon fibres in this post, Canyon incorporates a mix of carbon and basalt fibres in a specific lay-up pattern that supposedly allows for lots of flex fore and aft but not side to side.

Ergon CF3 Pro Carbon/ Canyon VCLS 2.0: Offered as both the Ergon CF3 Pro Carbon and the Canyon VCLS 2.0 (respective company heads Frank Arnold and Roman Arnold are brothers), this rather ingeniously designed seatpost splits the usual cylindrical cross-section into two halves. In essence, this creates two flat leaf springs that are inherently more prone to move upon impact but without adding undue bulk or mass. This is strictly a road/CX-only model, though, as it’s explicitly not approved for mountain bike use and carries a 100kg (220lb) rider-plus-gear weight limit.

Ritchey WCS Carbon Link FlexLogic: Much like the Canyon VCLS, Ritchey’s entry looks like any other typical carbon fibre seatpost from the outside. Beneath the skin, though, Ritchey says the fibre plies have been tuned to be more flexible under load over the company’s standard carbon offerings – by as much as 15% based on claims. The interchangeable head accepts Ritchey’s single-rail saddles, too, and this model is by far the lightest of the bunch.

Specialized CG-R: Certainly the most unusual looking of the bunch, the CG-R incorporates a pivotless carbon hinge up top plus an elastomer wedge that Specialized says provides up to 18mm of vertical movement along with “unsurpassed comfort, control, and efficiency without adding weight or complication to the frame.” As promised, it’s certainly light and the location of the flex mechanism doesn’t require much seatpost extension, which could be a boon for shorter riders.

Syntace P6 Carbon HiFlex: This seatpost follows the same philosophy as the Ritchey, resorting to careful fibre orientations to promote a smoother ride – “twice the shock absorption capabilities in the riding direction as previously”, at least according to Syntace. Notably, this is the longest seatpost in our test and carries no usage restrictions or weight limit so it’d also be a viable option for trail riding.

Thomson Elite: This stalwart model served as the benchmark for our test – a machined aluminum seatpost that has proven itself to be one of the most popular premium models ever produced as well as one of the most durable. We also chose this model for its well-documented firm ride quality. If ever there was a standard to be measured by, this is it.